Lathe



Nov.. 16], 1948. H D, CHAMBLISS Y 2,453,744

LATI-IE Filed May 1, 1946 3 Sheets-Sheet 3 INVENTOR H. DAHDEN CHANEL/S5' BYI A TTORNE T Patented Nov. 16, 1948 UNITED STATES oFFzlcE ii lClaires- This invention relates to a lathe attachment for the production of elliptical forms and particularly to a device that may be mounted upon a conventional lathe head to car-ry a chuck and operate the latter in an elliptical path.

Broadly considered, the present invention relates primarily to a novelland simple mechanism for converting rotary movement of one element into a lcombined rotary and translational or reciprocatory movement of a second element, with an adjustment provided to vary the size andshape of the ellipse described by the second element.

Devices having the same general function have been proposed heretofore, but they have been unnecessarily complex and costly. Therefore, it is the principal object yof my invention to provide a mechanismthat is sturdy and effective in design, yet simply made of a few inexpensive parts.

It is aA further major object of this invention to provide a mechanism, f the character above mentioned, embodying a novel, simple .and readily accessible adjusting means.

Another important `.object of my invention re,- sides in the provision of a micrometer device des signed for association with the lathe unit to facilitate accurate adjustment and variation of the .ellipse axes.

The foregoing and other objects will 4be ap.- parent from a study of the following description when taken in conjunction with Ithe acoomparliing draw-ings, wherein:-

Figure 1 is a s oniewhatA diagrammatic view in side elevation of a preferred form of :the present invention assembled between a lathe head and a .chuck- Figure 2 is a similar view showing the parts separated from one another-ign a direction axialllr of thelathe.

Figure 3 is a, front face view of the drive .plate that. is secured to the nose of the lathe head in Figure 1.

Figure 4 is a side elevational view yof the drive plate.

Figure 5 is an end elevational view of the same plate.

AFigure 6 is a face yiew of the controlling vunit which -is vadjustable to govern the movement of the chuck.

Figure 7 represents a sectional view .taken on the .plane oiline iI-, Figurel.

Figure :8 is la `front face `view of the member lthat .is .slidably `,ca-rioled by .the drive plate.

.Figure 191slanendeleyational view 50i-,the slide member.

Son

element of Figure 14.

Figure 16 shows, partially in section, the mi.- crometer barrel .ofV Figure 13 designed for cooperation with the element of Figure 15.

With continued reference. to the drawings, in Figures 1` and 2 there is shown a conventional lathe vhead 2.0. mounted upon a frame bed. 2l and designed for connection with any` suitable power source for driving its hollow shaft or spindle 22 having the usual externally threaded nose .end 22a. Aninternally threaded, work-holding chuck 23 ca n be screwed onto the nose 722a but, as illustrated, some .of the principal elements of the present invention are interposed between these parts to cause the .chuck to have a variable elliptical motion as well as to rotate truly on center.

`-The interposed vparts include a drive plateor member 24 that can be screwed upon or otherwise united to the threaded nose 22a of the spindle 22 to rotate bodily therewith, and also a stationary rod or shaft y25 (shown as a hollow shaft in Figure '7) that extends axially through the hollow spindle of the lathe head. Any suit.-

able -means may be utilized to prevent rotation of the shaft 25. For example, and for convenience vof illustration, a stiif wire yor rod `26 may pierce the youter end of the shaft and be bent, as seen in I igure 1, to engage `one side of the framework.

The'inner or otherend of the shaft 25 carries, concentricalily, a cylindrical and relatively thick block 21, xed `thereto by an integral, axial extension 245 that is -tted tightly within or screwed into` the sleeve `25. Obviously, `other available interconnecting means may be chosen. The block 21 nests into the plate 24, and the lat- .teris interlocked with aldriven plate 29 for unitary rotation, all` the details of which will be explained shortly. Theplate 29 has an axial extension 30, (preferably integral and externally threaded), for detachable connection with lthe chuck 213. The latter lpartakes .of a simple har.-

monic motion, in an elliptical path, as now to be explained.

The rotatable drive plate 24 (Figures 3 5) has a cylindrical recess 3| for nested reception of the stationary block 21. It also has a pair of parallel jaws, one integral (32) and the other detachable (33), to form a dovetailed channel or slideway for the connective reception of the driven plate or slide 29. The detachablejaw may be fastened to the plate 24 by screws 34. As previously mentioned, the drive plate may have threads 35 designed to secure it to the threaded nose 22a of the rotary spindle 22.

For the purposes of adjustment the plate 24 has a pair of diametrically opposed holes 36 through which the end of a tool element such as a screw driver or an Allen wrench may be inserted to reach certain elements about to be described. Also upon one jaw or the other of the assembled plate 24, there is adjustably mounted a vernier scale element 31 which, as presently seen, is important to the preselection of elliptical axes.

As shown best in Figure 3, the drive plate 24 has a recess or cavity 36 in that surface which faces the driven plate 29, the purpose being to avoid excessive friction. Adjacent the rends of this cavity there are (one at each end of the plate 24) a pair of slide surfaces 46 against which the driven plate may oscillate in simple harmonic motion.

The driven plate 29, as best lseen in Figures 8-10, comprises a body 42, designed to t within the jaws of the drive plate 24, and to slide in parallelism as well as to rotate therewith. The plate 29 has a groove 43, preferably of cylindrical curvature and opening outwardly, to receive a complemental sliding element 44 (Figures 1l and 12). of its at top, a cylindrical recess 45, for reception-with relative rotation-of a pin 46 integral with or secured to the adjustable unit 41 of Figures 6 and 7.

The adjustable unit 41 is simply a rectangular block that is slidable within a diametrical groove 48 in that face of the block 21 'which faces the driven element 29. The length of this groove governs the maximum eccentricity of the pin 46, which can be varied by locking the block 41 in various positions along the groove by means of a pair of coacting screw plugs 56. When the pin 46 is coaxial with the block 21 it has no tendency to vibrate the plate 29, and hence the chuck partakes of pure rotary motion. However, when the pin is set off center the plate 29 partakes of a sliding simple harmonic movement during its rotation, so that it travels in an elliptical path. The ellipse will have a difference in major and minor radii equal to the eccentricity of the pin.

For convenient adjustment of the screws 56 without dissembling the parts, they may be brought into alignment with the two previously described holes 36 in the surrounding drive plate, so that a tool such as an Allen wrench or screw driver may be inserted. The outer ends of the screws of course are shaped for interlocking coaction with the inserted tip of the tool. By loo-sening one screw and tightening the other, the block 41 is set to a preselected position which can be determined by bringing one end edge of the plate 29 or a mark thereon into register with a selected indicating line of the scale 31, Figure 3.

It should now be obvious that when the lathe head 26 rotates the drive member Z4. abOut The element 44 has, between the ends 4 the stationary block 21, the plate 29 rotates therewith and slides laterally of the rotational axis to a degree dependent upon the eccentricity of the pin 46, thus imparting an elliptical motion to the chuck 23.

Figure 13 discloses a drive member 52 similar to member 24 but modied to afford a micrometer adjustment for the screw plugs 50. For one of the holes 36 there is substituted a tapped recess 53 into which is screwed the complementally threaded end of a cylindrical barrel or sleeve 54 (see also Figure 16). The barrel is graduated lengthwise with an external scale 55. A passageway 56 in the body 52 permits a tool to be projected through the barrel and into connection with the proper screw plug 50 when alignment is brought about.

A suitable tool, Figure 14, comprises a handle 51 which may carry or have formed integral therewith a thimble 56 the base of which is snugly surrounded by a ferrule 60. A pin 6I passes through the ferrule, the base and one end of an elongated rod 62 that is set into the handle. The projecting tip 63 of the rod forms the tool element that engages the screw plug50 when the rod is passed through the barrel 54. It is undesirable that this element have a screw driver shape or any other shape that would permit it to enter the plug in more than one relative position. In other words, the illustrated T-shape or its equivalent ensures that the tool element must be rotated to a particular one position within la full circle before it can enter the screw plug.

The thimble 58 has an internal diameter very slightly greater than the outer diameter of the barrel 54 so that it can receive the latter when the tool is shoved into operating position. A peripheral scale 64 in the form of a ring of graduated lines is placed upon the thimble for cooperation with the scale of the barrel. The sets of graduations are so designed and correlated with respect to each other and the pitch of the screw threads on the plug 50 as to afford an accurate Vernier micrometer reading of the distance of the pin 46 from center (i. e., eccentricity) As seen in Figure 13, an indexing device may be provided to ensure that the proper screw plug 50 is aligned with the passage 56 when an adjustment is to be made. This device, as shown, comprises a stepped recess 65 containing a plunger 66 that has an integral pin 61 and a stem 68; a compression spring 10 surrounding the pin 61 and urging the plunger outwardly; and an externally threaded collar 12 screwed into the recess to limit the outward movement of the plunger. The relationship is such that, normally, the pin 61 does not quite extend into the large recess 3|, but can be caused to enter the latter by pushing upon the outer end of the stem 66. The cylindrical block 21, which occupies the recess 3l, may be notched at only one point (see notch 5l, Fig. 6) on the circumferential line that is passed by the indexing pin as the member 52 is rotated, the location of the notch being such that the pin engages it exactly when the proper screw plug 50 is aligned with the passage 56.

With the parts latched together as described, the eccentricity may rst be roughly adjusted by guess, or more accurately adjusted through use of a scale 31 such as seen in Figure 3. Then, by use of the micrometer parts 54 and 58, a nal adjustment of maximum or extreme accuracy is obtainable for preselection of the radii of the ellipse to be cut.

Since the anchored end of the barrel 54 is screwthreaded, it may be turned to move it into or back it out of the tapped recess 53 to obtain an initial correct setting for (zero) adjustment.

What is claimed is:

1. In combination, a lathe head having a hollow rotary drive shaft, a member connected to said shaft to be driven thereby, a stationary shaft extended through said hollow drive shaft and said member, said stationary shaft carrying an eccentric pin, and a driven element connected to said member to rotate therewith and to reciprocate radially with respect to the axis of rotation, said element having a transversely arranged groove into which said pin extends.

2. In the combination dened in claim 1, and means for adjusting the eccentricity of said pin.

3. In combination, a lathe head having a hol- W rotary drive shaft, a member connected to said shaft to be driven thereby, a stationary shaft extended through said hollow drive shaft and said member, said stationary shaft carrying an eccentric pin, a driven element connected to said member to rotate therewith and to reciprocate radially with respect to the axis of rotation, said element having a transversely arranged groove, a block slidable along said groove and receiving said eccentric pin, and means for adjusting the eccentricity of said pin.

4. In combination with a lathe head having a hollow drive shaft, a member connected to said shaft for rotation therewith, a stationary shaft extended through said hollow drive shaft and said member, said member having a recess, said stationary shaft carrying a block seated in said recess and having a diametrically arranged outwardly facing groove, a pin mounted in said groove for adjustment longitudinally thereof, adjusting means for varying the position of said pin and locking it in such position, and a driven element connected to said member to rotate therewith and to reciprocate radially with respect to the axis of rotation, said element having a radially arranged groove for slidable reception of the free end of said pin,

5. In the combination deiined in claim 4, said adjusting means comprising screw threads in said block and a pair of screw plugs tted in said threads at opposite sides of said pin, and said member having diametrically opposed apertures that can be aligned with said plugs to permit insertion of an adjusting tool.

6. In combination, a lathe head having a rotary shaft, a unit driven thereby and comprising a drive member secured to said shaft and having means forming a guide channel transverse to the i axis of rotation and facing outwardly from the lathe head, a slide element having parallel side edges confined by said guide channel so that said element rotates with said member and can reciprocate in said channel, a stationary element between said drive member and said slide element, one of said elements having a groove passing diametrically through the axis of rotation and the other carrying an adjustably mounted pin that extends into said groove, and means for varying the position of said pin.

7. In the combination dened in claim 6, said groove being located in the slide element in perpendicularity to said parallel side edges, and said pin mounted in said stationary element in parallelism with the axis of rotation.

8. In a machine of the class described, a drive member and a driven element intercoupled to rotate as a unit, the drive member on a iixed axis and the driven element further capable of sliding relative to said member in a straight line perpendicular to the axis of rotation, and a control device for causing a preselected amount of relative sliding movement during ea-ch cycle of rotation, said control device including -a stationary mounting element disposed between said drive vmember and said driven element, a pin shiftably mounted on one of said elements in parallelism with said xed axis and adjustable radially with respect thereto, and the other element having means receiving the free end of said pin and permitting relative travel ythereof on a line intersecting said fixed axis.

9. In the machine defined in claim 8, said other element having a groove that is cylindrically curved in cross-section, and a complementa] block slidable therein, said block having a lateral recess for the free reception of said pin.

lo In a machine of the class described, a rotary drive member recessed in one side con-centrically of its axis, a stationary element nested in the recessed side and having an outwardly facing radial slot, a radially adjustable pin having one end mounted in said slot in parallelism with said axis, a driven member coupled to said drive member at its recessed side and slidable transversely of said axis, said driven member having a groove receiving the other end of said pin, said drive member having a radial opening that can fbe aligned with said slot in one angular position of rotation to permit entry of a tool for changing the position of said pin, another substantially radial opening in said drive member, and an indexing device mounted in said last mentioned opening and engageable with said stationary element to latch said drive member thereto in said one angular position.

H. DARDEN CHAMBLISS.

REFERENCES CITED The following references are of record in the le of this patent:

UNrrED STATES PATENTS Number Name Date 209,397 King Nov. 12, 1878 1,269,413 Finnigan June 11, 1918 1,817,721 Van Hamersveld Aug. 4, 1931 

